Prevalence

Estimates of the prevalence of depression are affected by the nature of the measures used, how depression is defined, aging characteristics of the samples studied and when symptoms are assessed post-injury (Elliott & Frank 1996). The common research practice of employing self-report measures is both convenient and cost-effective. However, the resulting prevalence rates may reflect subjective anxiety and overall distress rather than symptoms specific to depression, per se. In clinical practice, self-report measures may serve to alert the clinician to the need for additional evaluation and can aid in monitoring symptom severity over time. For reviews of depression and other psychosocial measures frequently used in spinal injury research and practice see Vahle et al. (2000), Richards et al. (2006), Sakakibara et al. (2009), and SCIRE chapter 25 on outcome measures.

In a review, Bombardier et al. (2004) found rates of major depression or probable major depression following SCI vary widely across studies and can range from 7% to 31% of persons, with estimates of major depressive disorder typically reported in 15%-23% of individuals. In a recent survey of 568 adult traumatic SCI inpatient rehabilitation clients, approximately 22% met self-reported symptoms consistent with major depressive disorder on average less than two months post injury (Krause et al. 2008). Bombardier et al. (2004) surveyed 849 SCI outpatients at one-year post injury and found 11.4% met criteria for MDD. Krause et al. (2000) suggest a 42% overall rate of depression with a 21% probable rate of major depression – indicative of a 4-fold increase of depressive disorders among individuals with SCI when compared with samples of non-disabled individuals. Of note, many studies do not include information regarding use of antidepressants, other medications, or psychotherapeutic interventions in their reports. Accordingly, observed rates of depressive symptoms may potentially be a reflection of multiple additional factors and the “net effect of all treatments” (Krause et al. 2008).

With up to 25% of men and 47% of women affected (Consortium for Spinal Cord Medicine 1998) a recent case-matched comparison found an absence of gender differences in probable major depression and symptom severity (Kalpakjian & Albright 2006). In an Italian sample averaging 6 years post-SCI, Scivoletto et al. (1997) found 16% reported significant symptoms of depression and 13% anxiety. Migliorini et al. (2008) employed an Australian sample who averaged 19 years post-SCI, 37% were identified as depressed, 30% suffered anxiety, 25% experienced significant stress and 8.4% reported post-traumatic stress disorder. Of note, approximately 60% of individuals with one probable diagnosis were likely to suffer at least one other comorbid condition highlighting the potential complexity of mental health issues.

In a 6-year follow-up study of 233 Albertans with SCI, 28.9% were treated for depression following their traumatic SCIs, with approximately 59% of these individuals beginning treatment during their initial hospitalization (both acute and rehabilitation admissions). An additional 10% of people were treated during the remainder of the first year. This exceeded depression treatment rates reported in able-bodied controls of approximately 11% (Dryden et al. 2004) with those at highest risk reporting permanent neurological deficit, a pre-injury history of depression, or substance abuse (Dryden et al. 2005). Kennedy & Rogers (2000) reported that anxiety, depression and hopelessness gradually increased beginning at week 30 post injury and continued until discharge from rehabilitation (week 48). At that point 60% of SCI clients scored above a clinical cut-off for depression (i.e. Beck Depression Inventory). Krause et al. (2008) suggested that depressive symptoms may not peak during inpatient rehabilitation and it may take additional time for the “low point of emotional adaptation to appear”.

In a cross sectional study, Richardson & Richards (2008) found that rates of clinically significant depressive symptoms (PHQ-9 scores >10) were reported by approximately 21%, 18%, 12% and 12% of SCI survivors surveyed at 1, 5, 15 and 25 years post injury, suggesting rates tended to decrease with time since injury. Data obtained in earlier studies also suggested that in newly injured persons who met criteria for major and minor depression, many remit within 3 months of onset (Kishi et al. 1994) and that the frequency of reported problems decreases over the first year (Richards 1986). In a longitudinal analysis, Pollard & Kennedy (2007) found a substantial relationship between reported depressive symptoms at 3 months and approximately a decade post injury, with 38% and 35% of SCI survivors surveyed meeting a criterion for moderate depression at these times. Hoffman et al. (2008) followed 411 SCI model system participants and found approximately 20% of at 1 year post injury and 18% at year 5 post-injury reported symptoms consistent with major depression. Further, approximately a third of those reporting scores suggestive of moderate depression at year 1 experienced remission, while approximately 9% were newly depressed at year 5. The authors summarized that the natural history of depression post SCI was variable over time with some showing improvement while others exhibited emotional decline.

It has been questioned whether, despite its reported prevalence, efforts to improve the detection and treatment of depression in individuals with SCI has improved (Bombardier et al. 2004). In an editorial comment, Faber (2005) expressed concern that given possible underestimates, about half of all persons hospitalized for traumatic SCI may benefit from treatment for depression. Similarly, while a substantial percentage of their SCI clinic sample reported symptoms suggestive of major depression, Kemp & Krause (1999) found that none were receiving treatment (psychotherapy or medications). In a review of American veterans with spinal cord injuries and disabilities, Smith et al. (2007) concluded that many may not be receiving adequate treatment for depression and the authors encouraged more aggressive screening and treatment.

As health problems can produce pain, fatigue, sleep disturbances, physical sensations and digestive troubles, the overlap of somatic symptoms can pose diagnostic challenges. Krause, et al. (2008) noted that on average, nearly a third of a large sample of SCI adult inpatient rehabilitation clients cited sleep, energy and appetite changes, while symptoms of persistent depressed mood and anhedonia were reported by approximately 10% and 15% of the sample, respectively. In a large outpatient sample, 80% of SCI survivors with probable MDD reported symptoms of depressed mood, anhedonia, feelings of failure, disturbed sleep and decreased energy (Bombardier et al. 2004). In general, despite the potential for an increase in “false positives,” reports of somatic symptoms merit clinician review given their strong association with affective or more general symptoms of depression (Richardson & Richards, 2008; Krause et al. 2008).

Conclusions

While not universal, for many persons with spinal cord injury, depression can be a complication that poses a significant impediment to their functioning and adaptation.

Identifying depression can be difficult, but is most likely to develop during the initial year post-injury. Though many will experience a remission of symptoms over time, for others depressive symptoms may persist for many years.

Self-report measures of depression should be viewed as screening tools to alert the clinician to arrange a more thorough evaluation. In addition to affective symptoms, endorsement of somatic symptoms (e.g. sleep disturbance, poor energy and appetite disturbance) during inpatient or outpatient contact merits clinical review to clarify possible mechanisms underlying their emergence.